/*======================================================================*
    Copyright (c) 2015-2023 DTS, Inc. and its affiliates.

    Redistribution and use in source and binary forms, with or without modification,
    are permitted provided that the following conditions are met:

    1. Redistributions of source code must retain the above copyright notice, this
    list of conditions and the following disclaimer.

    2. Redistributions in binary form must reproduce the above copyright notice,
    this list of conditions and the following disclaimer in the documentation
    and/or other materials provided with the distribution.

    3. Neither the name of the copyright holder nor the names of its contributors
    may be used to endorse or promote products derived from this software without
    specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
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    (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 *======================================================================*/

#include "commonstream/hash/MD5Generator.h"

#include <stdio.h>
#include <string.h>
#include <iostream>

namespace CommonStream
{

#if __BYTE_ORDER == __BIG_ENDIAN
#define HIGHFIRST 1
#endif
    
#ifndef HIGHFIRST
#define byteReverse(buf, len)	/* Nothing */
#else
    void byteReverse(unsigned char *buf, unsigned longs);
    
#ifndef ASM_MD5
    /*
     * Note: this code is harmless on little-endian machines.
     */
    void byteReverse(unsigned char *buf, unsigned longs)
    {
        uint32_t t;
        do {
            t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
            ((unsigned) buf[1] << 8 | buf[0]);
            *(uint32_t *) buf = t;
            buf += 4;
        } while (--longs);
    }
#endif
#endif

    /*
     * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
     * initialization constants.
     */
    void MD5Generator::MD5Init(struct MD5Context *ctx)
    {
        ctx->buf[0] = 0x67452301;
        ctx->buf[1] = 0xefcdab89;
        ctx->buf[2] = 0x98badcfe;
        ctx->buf[3] = 0x10325476;
        
        ctx->bits[0] = 0;
        ctx->bits[1] = 0;
    }

    /*
     * Update context to reflect the concatenation of another buffer full
     * of bytes.
     */
    void MD5Generator::MD5Update(struct MD5Context *ctx, unsigned char const *buf, unsigned len)
    {
        uint32_t t;
        
        /* Update bitcount */
        
        t = ctx->bits[0];
        if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t)
            ctx->bits[1]++;		/* Carry from low to high */
        ctx->bits[1] += len >> 29;
        
        t = (t >> 3) & 0x3f;	/* Bytes already in shsInfo->data */
        
        /* Handle any leading odd-sized chunks */
        
        if (t) {
            unsigned char *p = (unsigned char *) ctx->in + t;
            
            t = 64 - t;
            if (len < t) {
                memcpy(p, buf, len);
                return;
            }
            memcpy(p, buf, t);
            byteReverse(ctx->in, 16);
            MD5Transform(ctx->buf, (uint32_t *) ctx->in);
            buf += t;
            len -= t;
        }
        /* Process data in 64-byte chunks */
        
        while (len >= 64) {
            memcpy(ctx->in, buf, 64);
            byteReverse(ctx->in, 16);
            MD5Transform(ctx->buf, (uint32_t *) ctx->in);
            buf += 64;
            len -= 64;
        }
        
        /* Handle any remaining bytes of data. */
        
        memcpy(ctx->in, buf, len);
    }
    
    /*
     * Final wrapup - pad to 64-byte boundary with the bit pattern
     * 1 0* (64-bit count of bits processed, MSB-first)
     */
    void MD5Generator::MD5Final(unsigned char digest[16], struct MD5Context *ctx)
    {
        unsigned count;
        unsigned char *p;
        
        /* Compute number of bytes mod 64 */
        count = (ctx->bits[0] >> 3) & 0x3F;
        
        /* Set the first char of padding to 0x80.  This is safe since there is
         always at least one byte free */
        p = ctx->in + count;
        *p++ = 0x80;
        
        /* Bytes of padding needed to make 64 bytes */
        count = 64 - 1 - count;
        
        /* Pad out to 56 mod 64 */
        if (count < 8) {
            /* Two lots of padding:  Pad the first block to 64 bytes */
            memset(p, 0, count);
            byteReverse(ctx->in, 16);
            MD5Transform(ctx->buf, (uint32_t *) ctx->in);
            
            /* Now fill the next block with 56 bytes */
            memset(ctx->in, 0, 56);
        } else {
            /* Pad block to 56 bytes */
            memset(p, 0, count - 8);
        }
        byteReverse(ctx->in, 14);
        
        /* Append length in bits and transform */
        ((uint32_t *) ctx->in)[14] = ctx->bits[0];
        ((uint32_t *) ctx->in)[15] = ctx->bits[1];
        
        MD5Transform(ctx->buf, (uint32_t *) ctx->in);
        byteReverse((unsigned char *) ctx->buf, 4);
        memcpy(digest, ctx->buf, 16);
        memset(ctx, 0, sizeof(MD5Context));	/* In case it's sensitive */
    }

    /* The four core functions - F1 is optimized somewhat */
    
    /* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))
    
    /* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) \
( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

    /*
     * The core of the MD5 algorithm, this alters an existing MD5 hash to
     * reflect the addition of 16 longwords of new data.  MD5Update blocks
     * the data and converts bytes into longwords for this routine.
     */
    void MD5Generator::MD5Transform(uint32_t buf[4], uint32_t const in[16])
    {
        uint32_t a, b, c, d;
        
        a = buf[0];
        b = buf[1];
        c = buf[2];
        d = buf[3];
        
        MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
        MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
        MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
        MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
        MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
        MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
        MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
        MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
        MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
        MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
        MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
        MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
        MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
        MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
        MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
        MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
        
        MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
        MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
        MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
        MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
        MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
        MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
        MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
        MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
        MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
        MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
        MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
        MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
        MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
        MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
        MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
        MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
        
        MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
        MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
        MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
        MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
        MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
        MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
        MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
        MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
        MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
        MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
        MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
        MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
        MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
        MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
        MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
        MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
        
        MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
        MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
        MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
        MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
        MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
        MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
        MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
        MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
        MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
        MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
        MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
        MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
        MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
        MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
        MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
        MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
        
        buf[0] += a;
        buf[1] += b;
        buf[2] += c;
        buf[3] += d;
    }

    MD5Generator::MD5Generator()
    {
        state_ = eHashState_Stopped;
    }
    
    MD5Generator::~MD5Generator()
    {
    }
    
    bool MD5Generator::stop(void)
    {
        if (state_ == eHashState_Stopped)
        {
            return true;
        }
        
        if ((state_ == eHashState_Started)
            || (state_ == eHashState_Paused))
        {
            state_ = eHashState_Stopped;
        }
        else
        {
            return false;
        }
        
        MD5Final(ss_, &ctx_);
        
        return true;
    }
    
    bool MD5Generator::accumulate(uint8_t *iValue, uint32_t iByteCount)
    {
        if (state_ == eHashState_Stopped)
        {
            return false;
        }
        else if (state_ == eHashState_Paused)
        {
            return true;
        }
        
        if (iByteCount == 0)
            return false;
        
        MD5Update(&ctx_, iValue, iByteCount);
        
        return true;
    }
    
    bool MD5Generator::start(void)
    {
        if (state_ == eHashState_Stopped)
        {
            MD5Init(&ctx_);
            state_ = eHashState_Started;
            return true;
        }
        else if ((state_ == eHashState_Started)
                 || (state_ == eHashState_Paused))
        {
            state_ = eHashState_Started;
            return true;
        }
        else
        {
            return false;
        }
    }
    
    CommonStream::EHashType MD5Generator::getHashType(void)
    {
        return CommonStream::eHashType_MD5;
    }
    
    CommonStream::HashGenerator::EHashState MD5Generator::getState(void)
    {
        return state_;
    }
    
    bool MD5Generator::useHash(void)
    {
        bool useHash = (state_ == eHashState_Started) || (state_ == eHashState_Paused);
        
        return useHash;
    }
    
    bool MD5Generator::pause(void)
    {
        if ((state_ == eHashState_Paused) || (state_ == eHashState_Started))
        {
            state_ = eHashState_Paused;
        }
        else
        {
            return false;
        }
        
        return true;
    }
    
    bool MD5Generator::resume(void)
    {
        if (state_ == eHashState_Paused)
        {
            state_ = eHashState_Started;
        }
        else
        {
            return false;
        }
        
        return true;
    }
    
    uint32_t MD5Generator::getHashSize()
    {
        return 16;
    }
    
    bool MD5Generator::getHash(uint8_t *oHash)
    {
        memcpy(oHash, ss_, 16);
        
        return true;
    }

}  // namespace CommonStream
